tingle15 wrote:
A master builder is building a new house. He gets 3 apprentices who EACH work 2/3 as fast as he does. If all 4 work on it together, they should finish it in what fraction of the time that it would have taken the master builder working alone?
A) 4/7
B) 1/3
C) 2/3
D) 3/4
E) 4/3
let time for builder alone to finish=3 days
builder's rate=1/3
apprentice rate=2/3*1/3=2/9
1/(1/3+6/9)=1 day for builder/apprentices to finish
1 day/3 days=1/3
B
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